Technological application of semiconductors depends critically on their defect properties. Recently, it has been experimentally observed that monolayer (ML) black phosphorus (BP) and black arsenic (BAs) are intrinsic p-type semiconductors, which conflict with the theoretical predictions previously acknowledged that there are no shallow defects in two-dimensional semiconductors. In this paper, we have systematically studied the properties of intrinsic defects in ML BP and BAs using the “transfer to real state” model. We confirmed that both P and As vacancies are shallow dominating acceptors, resulting in the p-type conductivity in ML BP and BAs, respectively. These shallow acceptor levels arise from the symmetry lowering induced by the large local structural distortion for the charged vacancy state. To validate our simulation, we also calculated the hole concentrations that are consistent with the experimentally measured p-type conductivity in both materials. Our results, therefore, help explain the origin of the intrinsic p-type conductivity in ML BP and BAs, which reinforces the comprehension for the defect properties in two-dimensional materials.

中文翻译：

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大晶格弛豫诱导的单层黑磷和黑砷中的固有浅p型特征

半导体的技术应用主要取决于其缺陷性质。最近，已经通过实验观察到，单层（ML）黑磷（BP）和黑砷（BAs）是本征p型半导体，这与先前承认二维半导体中不存在浅缺陷的理论预测相冲突。在本文中，我们使用“转移到真实状态”模型系统地研究了ML BP和BA中固有缺陷的性质。我们确认，P和As空位都是浅的主要受体，分别导致ML BP和BA中的p型电导率。这些浅受体水平是由带电空位状态的大局部结构变形引起的对称性降低引起的。为了验证我们的模拟，我们还计算了两种材料中与实验测量的p型电导率一致的空穴浓度。因此，我们的结果有助于解释ML BP和BA中固有的p型电导率的起源，从而增强了对二维材料中缺陷性质的理解。